Topics related to Lumerical and more

bent waveguide problem in MODE

    • Jingda Wu

      I am designing a ring resonator and using MODE to simulate the bending loss and neff. However, I find the result is very inconsistent depending on where the origin is set. 


      In the original simulation of the lumerical example, the simulation center is at x=-0.1um, and a bending radius r=1.5um and here's the result



      Then if I set the FDE origin to be x=0 and bending radius r=1.6um, The result is totally different.



      This kind of inconsistency continues with user specified bend location. This makes it difficult to simulate complex structures. Is there a reason behind this inconsistency?

    • Guilin Sun
      Ansys Employee

      You are completely correct and it is expected. Please check this article:

      Basically, it calculates the angular propagation constant and converts it to the linear porpagation constant:

      while the angular "beta" is constant, the radius ca be arbirary. Therefore, you will need to correct the result using 


      then the result will be constant when you change the bent center and bending radius. Please try and let me know if you have question.

    • Jingda Wu

      I see. Thanks for the clarification.

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